LONDON (AFP) - Prime Minister Tony Blair destabilized politics in Northern Ireland by pandering to the Sinn Fein Catholic party's demands, according to a leading architect of the peace accord.

Seamus Mallon, an architect of the Good Friday Agreement, accused Blair of acting in "bad faith" by making private deals with Sinn Fein president Gerry Adams, while ignoring other politicians.

Mallon, a former leader of the moderate nationalist SDLP, told Wednesday's edition of the Daily Telegraph that Downing Street's tactics will result in a long-term stagnation in Northern Ireland political negotiations after trust in Blair's word had evaporated.

Mallon warned that the government's approach had "wiped out" the middle ground by catering instead to the extremists.